1. Field of Invention
The invention relates to a switching device and, in particular, to a device for switching audio signals and the method thereof.
2. Related Art
With the rapid development in information technology, computers and their peripherals become very popular. Computer users often use the mouse and keyboard to control the computers. Through the monitors or speakers, the computer users can monitor the state of the computers. Sometimes a user may have more than one computer to process different types of things. Traditionally, each computer is equipped with one set of input/output (IO) peripheral devices, including the keyboard, mouse, monitor, and speakers. However, this is a waste of money and space if one has several computers.
On the other hand, large system businesses or enterprise internal networks often involve tens to thousands servers. Each server needs a monitor, a keyboard and a mouse to for management. In practice, one rarely needs to use these IO peripherals of the servers. Most of the time, the servers do not need to be controlled by the manager. In this situation, it is totally unnecessary, costly, and wasting the space to have a set of IO peripheral devices for each server.
Therefore, a switching device that enables one to use one set of IO peripheral devices to manage several computers has been proposed to solve this problem. The use of a switching device does not only save the cost, it also solve the space and compatibility problems.
However, conventional switching devices do not have a good performance in switching audio signals. For example, the DC levels of audio signals output from different sound cards may vary. This may result in sound blast during the switching. Moreover, if the switching device also process other IO peripheral devices that consume high power at the same time, the DC level in the switching device will float as a result of the huge power consumption elsewhere. This will generate the problem of audio interference.
Moreover, conventional switching devices often use mechanical relays to switch. However, the mechanical switching device has a limited lifetime. It is likely to have spark during the switching. Therefore, it may cause damages to the switching device or even hurt the devices inside the computer.